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.Dd November 10, 2022
.Dt CXGBEV 4
.Os
.Sh NAME
.Nm cxgbev
.Nd "Chelsio T4-, T5-, and T6-based 100Gb, 40Gb, 25Gb, 10Gb, and 1Gb Ethernet VF driver"
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device cxgbe"
.Cd "device cxgbev"
.Ed
.Pp
To load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_cxgbev_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for Virtual Functions on PCI Express Ethernet adapters
based on the Chelsio Terminator 4, Terminator 5, and Terminator 6 ASICs
(T4, T5, and T6).
The driver supports Jumbo Frames, Transmit/Receive checksum offload,
TCP segmentation offload (TSO), Large Receive Offload (LRO), VLAN
tag insertion/extraction, VLAN checksum offload, VLAN TSO, and
Receive Side Steering (RSS).
For further hardware information and questions related to hardware
requirements, see
.Pa http://www.chelsio.com/ .
.Pp
The
.Nm
driver uses different names for devices based on the associated ASIC:
.Bl -column -offset indent "ASIC" "Port Name"
.It Sy ASIC Ta Sy Port Name Ta Sy Parent Device
.It T4 Ta cxgbev Ta t4vf
.It T5 Ta cxlv Ta t5vf
.It T6 Ta ccv Ta t6vf
.El
.Pp
Loader tunables with the hw.cxgbe prefix apply to VFs from all cards.
The Physical Function driver for Chelsio Terminator adapters shares these
tunables.
The driver provides sysctl MIBs for both ports and parent devices using
the names above.
For example, a T5 VF provides port MIBs under dev.cxlv and
parent device MIBs under dev.t5vf.
References to sysctl MIBs in the remainder of this page use
dev.<port> for port MIBs and dev.<nexus> for parent device MIBs.
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh HARDWARE
The
.Nm
driver supports Virtual Functions on 100Gb and 25Gb Ethernet adapters
based on the T6 ASIC:
.Pp
.Bl -bullet -compact
.It
Chelsio T6225-CR
.It
Chelsio T6225-SO-CR
.It
Chelsio T62100-LP-CR
.It
Chelsio T62100-SO-CR
.It
Chelsio T62100-CR
.El
.Pp
The
.Nm
driver supports Virtual Functions on 40Gb, 10Gb and 1Gb Ethernet adapters
based on the T5 ASIC:
.Pp
.Bl -bullet -compact
.It
Chelsio T580-CR
.It
Chelsio T580-LP-CR
.It
Chelsio T580-LP-SO-CR
.It
Chelsio T560-CR
.It
Chelsio T540-CR
.It
Chelsio T540-LP-CR
.It
Chelsio T522-CR
.It
Chelsio T520-LL-CR
.It
Chelsio T520-CR
.It
Chelsio T520-SO
.It
Chelsio T520-BT
.It
Chelsio T504-BT
.El
.Pp
The
.Nm
driver supports Virtual Functions on 10Gb and 1Gb Ethernet adapters based
on the T4 ASIC:
.Pp
.Bl -bullet -compact
.It
Chelsio T420-CR
.It
Chelsio T422-CR
.It
Chelsio T440-CR
.It
Chelsio T420-BCH
.It
Chelsio T440-BCH
.It
Chelsio T440-CH
.It
Chelsio T420-SO
.It
Chelsio T420-CX
.It
Chelsio T420-BT
.It
Chelsio T404-BT
.El
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width indent
.It Va hw.cxgbe.ntxq
Number of tx queues used for a port.
The default is 16 or the number
of CPU cores in the system, whichever is less.
.It Va hw.cxgbe.nrxq
Number of rx queues used for a port.
The default is 8 or the number
of CPU cores in the system, whichever is less.
.It Va hw.cxgbe.holdoff_timer_idx
Timer index value used to delay interrupts.
The holdoff timer list has the values 1, 5, 10, 50, 100, and 200
by default (all values are in microseconds) and the index selects a
value from this list.
The default value is 1 which means the timer value is 5us.
Different interfaces can be assigned different values at any time via the
dev.<port>.X.holdoff_tmr_idx sysctl.
.It Va hw.cxgbe.holdoff_pktc_idx
Packet-count index value used to delay interrupts.
The packet-count list has the values 1, 8, 16, and 32 by default,
and the index selects a value from this list.
The default value is -1 which means packet counting is disabled and interrupts
are generated based solely on the holdoff timer value.
Different interfaces can be assigned different values via the
dev.<port>.X.holdoff_pktc_idx sysctl.
This sysctl works only when the interface has never been marked up (as done by
ifconfig up).
.It Va hw.cxgbe.qsize_txq
Number of entries in a transmit queue's descriptor ring.
A buf_ring of the same size is also allocated for additional
software queuing.
See
.Xr ifnet 9 .
The default value is 1024.
Different interfaces can be assigned different values via the
dev.<port>.X.qsize_txq sysctl.
This sysctl works only when the interface has never been marked up (as done by
ifconfig up).
.It Va hw.cxgbe.qsize_rxq
Number of entries in a receive queue's descriptor ring.
The default value is 1024.
Different interfaces can be assigned different values via the
dev.<port>.X.qsize_rxq sysctl.
This sysctl works only when the interface has never been marked up (as done by
ifconfig up).
.It Va hw.cxgbe.interrupt_types
Permitted interrupt types.
Bit 0 represents INTx (line interrupts), bit 1 MSI, and bit 2 MSI-X.
The default is 7 (all allowed).
The driver selects the best possible type out of the allowed types.
Note that Virtual Functions do not support INTx interrupts and fail
to attach if neither MSI nor MSI-X are enabled.
.It Va hw.cxgbe.fl_pktshift
Number of padding bytes inserted before the beginning of an Ethernet
frame in the receive buffer.
The default value of 2 ensures that the Ethernet payload (usually the IP header)
is at a 4 byte aligned address.
0-7 are all valid values.
.It Va hw.cxgbe.fl_pad
A non-zero value ensures that writes from the hardware to a receive buffer are
padded up to the specified boundary.
The default is -1 which lets the driver pick a pad boundary.
0 disables trailer padding completely.
.It Va hw.cxgbe.buffer_packing
Allow the hardware to deliver multiple frames in the same receive buffer
opportunistically.
The default is -1 which lets the driver decide.
0 or 1 explicitly disable or enable this feature.
.It Va hw.cxgbe.allow_mbufs_in_cluster
1 allows the driver to lay down one or more mbufs within the receive buffer
opportunistically.
This is the default.
0 prohibits the driver from doing so.
.It Va hw.cxgbe.largest_rx_cluster
.It Va hw.cxgbe.safest_rx_cluster
Sizes of rx clusters.
Each of these must be set to one of the sizes available
(usually 2048, 4096, 9216, and 16384) and largest_rx_cluster must be greater
than or equal to safest_rx_cluster.
The defaults are 16384 and 4096 respectively.
The driver never attempts to allocate a receive buffer larger than
largest_rx_cluster and falls back to allocating buffers of
safest_rx_cluster size if an allocation larger than safest_rx_cluster fails.
Note that largest_rx_cluster merely establishes a ceiling -- the driver is
allowed to allocate buffers of smaller sizes.
.El
.Pp
Certain settings and resources for Virtual Functions are dictated
by the parent Physical Function driver.
For example, the Physical Function driver limits the number of queues
available to a Virtual Function.
Some of these limits can be adjusted in the firmware configuration file
used with the Physical Function driver.
.Pp
The PAUSE settings on the port of a Virtual Function are inherited from
the settings of the same port on the Physical Function.
Virtual Functions cannot modify the setting and track changes made to
the associated port's setting by the Physical Function driver.
.Pp
Receive queues on a Virtual Function always drop packets in response to
congestion
.Po
equivalent to setting
.Va hw.cxgbe.cong_drop
to 1
.Pc .
.Pp
The VF driver currently depends on the PF driver.
As a result, loading the VF driver also loads the PF driver as a
dependency.
.Sh SUPPORT
For general information and support,
go to the Chelsio support website at:
.Pa http://www.chelsio.com/ .
.Pp
If an issue is identified with this driver with a supported adapter,
email all the specific information related to the issue to
.Aq Mt support@chelsio.com .
.Sh SEE ALSO
.Xr arp 4 ,
.Xr cxgbe 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 11.1
and
.Fx 11.1 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Navdeep Parhar Aq Mt np@FreeBSD.org
and
.An John Baldwin Aq Mt jhb@FreeBSD.org .
